The present invention relates to a plate exchanging apparatus and method in a rotary printing press, which automatically removes an,old plate from a plate cylinder and setting a new plate on the plate cylinder.
As a plate exchanging apparatus of this type, one is generally disclosed in Japanese Patent Laid-Open No. 11-77968. The plate exchanging apparatus disclosed in this reference has a cassette which is swingably supported by frames and has a new plate setting unit for setting a new plate and an old storage unit for storing an old plate, and an actuator for reciprocating the cassette between a plate mounting position and a retreat position. In this arrangement, when the cassette is moved from the retreat position to the plate mounting position by the actuator, the distal end of the cassette opposes the plate fixing unit of the plate cylinder. When the plate cylinder rotates almost one revolution from this state, an old plate whose leading and trailing edges are released from the plate fixing unit of the plate cylinder is stored in the old plate storage unit of the cassette.
In the conventional plate exchanging apparatus described above, however, the old plate may contact the inner surface of the old plate storage unit during the storage of the old plate in the old plate storage unit, thereby damaging the surface of the old plate.
It is an object of the present invention to provide a plate exchanging apparatus and method in a rotary printing press, which can prevent damage to the surface of an old plate during plate removal and bending of the old plate, thereby reliably reusing the old plate.
In order to achieve the above object of the present invention, there is provided a plate exchanging apparatus in a rotary printing press for removing an old plate unfixed from a plate cylinder having a plate fixing unit and setting a new plate on the plate cylinder by the plate fixing unit, comprising first control means for executing a full-automatic plate exchanging mode to automatically remove the old plate from the plate cylinder and automatically set the new plate on the plate cylinder using plate holding means, and second control means for executing a semi-automatic plate exchanging mode to remove the old plate from the plate cylinder by a combination of automatic and manual operations and set the new plate on the plate cylinder by a combination of automatic and manual operations.